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Monday, August 31, 2015

The Colorado Mine Waste Spill: The Fix That Broke

On Wednesday, Aug. 5, heavy-equipment operators employed
by the U. S. Environmental Protection Agency (EPA) were working at the site of
the abandoned Gold King mine near Silverton, which is about a hundred miles
northeast of the Four Corners area in southwestern Colorado.The mine had not operated since 1923,
and the workers weren't trying to get gold out of the mine.Instead, they were trying to make sure
that thousands of gallons of toxic-mineral-laden water that had filled large
parts of the mine would stay there.Their efforts were part of a larger project to clean up some nearby mines,
an effort that would be spoiled if toxic water were to leak out of the Gold
King mine and run downhill to the other mines.

So, the workers had good intentions.But good intentions don't always stop
bad things from happening.

It turned out that there was a lot more water backed up
behind the "adit" (the horizontal mine opening) than the workers
realized.Apparently, if they had
bored a test hole beforehand, they might have determined from the high pressure
that it was dangerous to do what they were doing.But bore holes cost money and time, the geology of the site
made such a project tricky, and so they went ahead with some shoring-up
operations.

Exactly what happened has not yet come to light, but
somehow, the actions of the construction machinery disturbed the delicate
balance of whatever loose rock was keeping the water in the mine, and here it
came.Some veiled references about
prompt action preventing fatalities imply that things must have gotten pretty
exciting for a while, as a flood of yellow acid water poured from the mine's
opening down the hill to find its way to Cement Creek, where it spread to
watersheds that cover parts of three states.Some of these now-polluted streams pass through Indian
reservations, and the Navajo Nation's president Russell Begaye has declared
that his tribe is going to sue the EPA.

Clearly, the EPA has a mess on its hands.But what about those good
intentions?Doesn't that count for
anything?

The Gold King spill has drawn attention to an ongoing
problem shared by many regions where mining was carried out with more
enthusiasm than wisdom by operators who did only what they had to do to get the
gold out.As anyone knows who as a child
played in sand on the beach with a toy shovel, holes in the ground dug
below the water table eventually fill up with water.Abandoned mines often contain soluble compounds such as iron
sulfide (pyrite, or fool's gold) and minerals containing toxic elements such as
lead, cadmium, and arsenic.When
water gets into these mines, the water acquires significant concentrations of
these undesirable chemicals, and oxidized pyrite makes it highly
acidic.Sooner or later, water
usually finds its way out of an old mine, either through natural fissures in
the rock or more violently as water pressure builds up and breaches blockages,
which is what happened at the Gold King mine, with a little accidental help
from the EPA.

What one generation messed up, a succeeding generation is
trying to clean up, but the task is Herculean—or maybe even Sisyphean.Sisyphus was a mythological Greek king
who played tricks on the gods.The
gods, in particular Zeus, didn't appreciate this, and so when Sisyphus died,
Zeus condemned him in Hades to try to roll a boulder up a hill.Just as he'd get nearly to the top, the
enchanted boulder would elude his grasp and roll back downhill, and Sisyphus
had to lather, rinse, and repeat, so to speak—forever.

The EPA won't have to clean up mines forever, but with
22,000 abandoned mines in Colorado alone, they have enough to keep them busy
for quite a while.The fact that
the EPA has resources to prevent mine-water spills at all is due to the passage
of laws such as the Superfund act, which helps pay to clean up environmental
messes that the owners (or former owners) can't afford to fix.The agreement under which the EPA was
working on the Gold King mine wasn't a full-fledged Superfund situation (such a
label was feared to discourage tourism), but millions of government dollars were committed to the cleanup anyway.And it was in pursuit of this type of cleanup that the site
workers inadvertently caused exactly the kind of problem that they were there
to prevent.

There is an opportunity here, even in this crisis, for
engineers and engineering educators.It's hard enough to dig a mine without having it fall on your head, but
as numerous accidents have shown, digging a mine is a piece of cake compared to
trying to do anything with an old abandoned mine for which few records exist
and maintenance ceased decades ago.But doing the kind of thing that the EPA is doing is engineering
too—pure-D environmental engineering, but probably not of a kind that too many
environmental engineering departments consider.

With so many abandoned mines to fix and federal money to
fix them, one can imagine a new engineering subdiscipline of abandoned-mine
remediation.Typically, new
engineering disciplines are practiced under other guises for some time before
anyone recognizes them as distinct from previous disciplines.For all I know, there may be a division
of some civil engineering department somewhere that already teaches these
things, but I doubt it.If there
isn't, though, there ought to be.

Maybe all the education in the world might not have
prevented the breach that caused the Gold King spill.Sometimes a bad thing is bound to happen no matter what you
do.But now that we've had a bad
example of how not to handle
abandoned mines, maybe the academics and engineers can get together to develop best practices and procedures to prevent things like this from happening
in the future.

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